All multi-cellular animals must transport fluids and gases to an from all cells of the body. In many instances this process is achieved by branching tubular organs with lumen by epithelial cells. In vertebrates, organs composed of branching tubes include the vasculature system, lungs, pancreas, and kidney. In vertebrates, the tracheal system of Drosophila is a branching tubular organ conserved at the molecular level; e.g., both require the reiterative use of an FGF receptor tyrosine kinase (RTK) signaling pathway. A unique environment within the Massachusetts General Hospital is providing an opportunity to elucidate pulmonary development from flies to humans. The identification of genetic analyses of conserved molecules that function during normal tracheal development in flies will guide the analyses of these same molecules during mammalian lung development. These integrated, comparative studies, therapies and/or therapeutics that will positively impact the treatment of the pulmonary hypoplasia associated with the common and tragic malformation Congenital Diaphragmatic Hernia. Project 2. Regulators of Tracheal Morphogenesis to Drosophila Using Drosophila as a model system, a genome wide screen has identified regions encoding genes that modify the function of Csw, a tyrosine phosphatase that transduces RTK signals, including those required for tracheal morphogenesis. Six regions that enhance and 14 that suppress Csw function encode genes not presently identified as components of RTK signaling. The goal of Aim 1 is to identify which regions alter tracheal development, and then to isolate and characterize selected modifiers of tracheal development. Building upon findings from chick and mouse animal models (Project 1 and 4), as well as genomic and chromosomal analyses derived from the study of patients with CDH (Project 4) the goal of Aim 2 is to analyze conserved genes functioning during tracheal morphogenesis. We will determine if Drosophila homologues of genes expressed during lung morphogenesis are conserved in flies. If so, we will genetically characterize selected Drosophila homologues to elucidate their functions during tracheal development. The goal of Aim 3 is to establish Drosophila as a model genetic system to search for new, or analyze existing pulmonary therapeutics. As in vertebrates, tracheal morphogenesis in flies is modified by the molecular environment. Drosophila will be used to screen existing "lung maturing" therapeutics, antioxidants, and selected drugs (Project 3) for their effects on the developing tracheal system. As the first step toward an ultimate goal to develop new lung maturing therapies, we will modify the environment with these compounds to create a "sensitized background" from which to screen for genes whose functions are modified by the compound.